You may think novelists always have fixed plans to which they work, so that the future predicted by Chapter One is always inexorably the actuality of Chapter Thirteen. But novelists write for countless different reasons. ... Only one same reason is shared by all of us: we wish to create worlds as real as, but other than the world that is. Or was. This is why we cannot plan. We know a world is an organism, not a machine. We also know that a genuinely created world must be independent of its creator; a planned world (a world that fully reveals its planning) is a dead world.
John Fowles